Recently, I purchased two Postwar Lionel #400 powered RDC Budd cars. I wanted one of the trailing dummies, but the prices on those are ridiculous. So, I went the cheaper route and bought two powered units and had the following options. Take the motor out of one of them..........set the e-units locked on forward for both e-units or........tether them together and run off one e-unit. I have experience with that process (noted in a recent thread I posted) of putting a motor in the dummy unit of an Alco set and linking them via tether. It works great and they are pulling animals now. I really wanted to tether these Budds, but I wanted to make sure that whatever I did was reversible and wouldn't leave a permanent "footprint". It was easier to run the tether in the Alcos because there is a natural hole in the rear door of both units that I could run the wires through. I had to search around a bit after I received these Budds and the slots behind the rear lamp holder seemed like a good candidate. The following photos are hopefully helpful in showing the pathway and connections. I always add LEDs to my mods and for these units I decided to use Evans Mega-chips right behind the dual headlights. As usual they are "torches".
-Roger